During surgical procedures, catheter introducers are often used to provide a conduit for passage of catheters and other relatively long, thin and flexible medical devices, for example, guide wires, into lumens in a patient. For example, in cholangiography procedures, an introducer is used to establish a guide channel to permit advancement of a catheter to an incision in the wall of the cystic duct of the gallbladder. The catheter is introduced through the introducer, under control of the surgeon, and is extended out of the introducer. The distal tip of the catheter is manipulated by the surgeon into the incision in the cystic duct, and navigated by the surgeon through the lumen of the cystic duct forward and through the valve of Heister. During this procedure, the valves or other obstructions can inhibit the catheter's advancement in the duct.
Prior art catheter introducers include a cannula and a hub mounted on a proximal end of the cannula. The cannula is generally straight in profile, and the catheter passes through the distal end of the cannula along the same axis as the cannula. During the surgical procedure, the surgeon typically approaches the cystic duct at some oblique angle to its longitudinal axis. Depending on the approach angle, a straight introducer may direct the catheter directly into the opposite wall of the duct, and may require pushing against the back wall of the duct in order to bend the catheter and direct it into the lumen of the duct. The elasticity of the duct wall makes such a procedure very difficult.
Some prior art introducers utilize a curved distal end to direct the catheter into the cystic duct. The curved introducers represent an improvement over the straight introducers, but still do not provide the support and control necessary for optimized catheter insertion. In general, both straight and curved introducers share a common problem. Laparoscopic procedures are difficult to execute because the surgeon is operating with instruments on an extended lever arm. For a cholangiography, a catheter must be inserted into a small incision in the cystic duct, the narrowest of the extra-hepatic ducts, which is generally 3 to 7 mm in diameter. With existing cholangiography procedures, the surgeon must be able to transmit navigation motions to insure that the catheter is properly inserted into the incision in the duct. Existing introducers do not have a tip which is optimized for providing access of the catheter to the cystic duct. While existing introducers may enable the surgeon to navigate the end of the catheter proximate the incision, they still require that the surgeon enter the incision with the end of the catheter, which can be difficult, given the necessary flexibility of the catheter, the diameter of the catheter and the typical dimensions of the incision.
What is needed is an improved catheter introducer which may be easily inserted into the cystic duct, and may be easily manipulated for laparoscopic cholangiograms.